Vertical nystagmus as isolated presentation in a patient with new diagnosis of multiple sclerosis.

Multiple sclerosis (MS) is a progressive demyelinating disease of the central nervous system with a wide array of symptoms. We present a healthy young woman who came to the Emergency Department with two days of isolated vertical nystagmus and was subsequently diagnosed with MS on imaging. Although bilateral vertical nystagmus is not a common presentation of MS, its presence should prompt inclusion of this disease process in the differential diagnosis.